This application claims priority of Taiwanese Application No. 090129634, filed on Nov. 28, 2001.
1. Field of the Invention
This invention relates to an electrochromic material, more particular to an electrochromic material and a method using electroless plating techniques for making the same.
2. Description of the Related Art
An electrochromic material normally includes a transparent substrate, a transparent conductive film formed on the substrate, and a metal oxide film formed on the conductive film. The metal oxide film, such as nickel oxide, can exhibit electrochromic characteristics when an electrical potential is applied thereto. The metal oxide film is formed by deposition of a metal film on the conductive film, followed by oxidizing the metal film. Conventionally, the metal film can be formed by a wet process, such as electrochemical deposition, sol-gel techniques, and spin-coating techniques, or by a dry process, such as vacuum evaporation, sputtering techniques, and electrode deposition. The sputtering techniques, such as rf-sputtering and reactive dc magnetron sputtering, require expensive equipment and a relatively large space. The sol-gel techniques may suffer from poor quality of the resulting metal film during removal of solvent upon heating. The electrode deposition suffers from poor cyclic ability and high aging rate of the metal oxide film.
Therefore, the object of the present invention is to provide a method using electroless plating techniques for making an electrochromic material that is capable of overcoming the aforementioned drawbacks of the prior art.
According to the present invention, there is provided a method for making an electrochromic material. The method comprises the steps of: (a) forming a transparent conductive film on a transparent substrate so as to form a plating substrate; (b) forming a metal film on the transparent conductive film of the plating substrate by electroless plating; and (c) oxidizing the metal film so as to form a metal oxide film, which exhibits electrochromic characteristics when an electrical potential is applied thereto, on the transparent conductive film.